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f, 0E BALTIMORE, MARYLAND.V A l 'Leiters Patent No. 78,073, dated May19, 186s.

IMPROVEMENT Ill4 BRIDGES.

itin tlgehnle retentit to it these tttet steut submitting miti ut thetime. v

TO ALL WHOM IT MAY -CONCERNz` l i Be it Yknown that we, EDWARD DENMEAD,oflvlarietta, inthejoo-unty of Cobb, and State o f Georgia, and WENDELBOLLMAN, `of Baltimore, .in the State of Maryland, have invented certain`new and useful :improvements in the Construction of Bridges; and we dohereby declare the following to be afull, clear, andexact descrip tionof the same, reference being had to the accompanying drawings, making apart of this speciiication, in,A

which- Figure 1 represents a top plan of so much of a bridge as willillustrate our invention. Figure 2 represents an elevation of the same,and i Figure 3 represents a vertical cross-section, taken at the redline a: :11, of iig. 2. Y Figures 4, 5,"and 6 represent, by similarviews, a modification of the general plan, lig. A(ibeing a verticalcross-section, taken at the red line y y of tig. 5.

Similar letters -of reference, where they occur in the several separatefigures, denote jlike parts in all ol the drawings. -4 i. l f

Our invention consists, rst, in supporting the angle-irons ofthe'bridgb'upon bolts which pass throughthe chords, instead of upon thechords, as heretofore done. 1

And, secondly, our inventionconsists inV the interposition, between theangle-irons and the chord/s, of rubber, felt, wood, or any other elasticcushion, to break the suddenness of thecontact and strain betweensaidtwo parts when heavy loads are passing.y p

To enable others skilled in the art `to make and use our invention, wewill proceed to describe the same with reference to the drawings.

A A represent a series of iron lchords, and B B. suspension-rods, suchas are used in bridge-building` InV figs. 1, 2, 3,A we have shown thechords as supported by a bolt, C, which passesthrough eyeswroughttherein, said bolt C being suspended to the top chords bythesuspension-rodsB B, andthe bearer suspended thereto by separate rods, B.In figs. 4, 5, 6, we have shown thc chords A as resting upon a'bearing-piece or pieces, D,

which bearing-piece or pieces are held by the suspension-rods B: Eitherform of sustaining the chords maybe used, asmiiybe prefcrrcd. Ourinvention does not relate to the chordsr or suspensionrods, or the modeof uniting them.A

Through the chords, as shown at 4, 5, 6, there is passeda bolt, C, butit is not a bearmgbolt for the chords,

as that in the plan shown in ligs. 1, 2, 3. .The bolts '0, in bothmodifications of construction, are used for u support for theangle-irons E, which heretofore have been supported upon the chords,which is found to be objectionable.l When, as is'shown at figs. 1, 2,and 3, the bolt C is suspended to or by the rods B, and the rods Bsuspended to the bolt C, thenthc anglo-iron E lcanV be supported on saidbolt Vin a central position, or by bearings in a vertical plane to itscentre; but, when the suspension-rods B pass by the chords, andcxtenddown to the bearing-piece D, to support it, as iniigs. 4, 5, 6, then thebolt C must be placed at one sidc-oi"these suspensionrods,and theangle-iron E, in that oase, would have its support outside 0f itscentral line, us seen in iigl 6, bu-t nevertheless it is a boltsupp'ort,instead of a chord-support, and `makes a better bearing for the angleiron, and relieves the chords; and, to still furthenreleve theangle-iron and chord of the sudden weight orjar p of a heavyload, 4weplace an elastic substance, a, between the angle-iron and the chords,which cushions the' load und'strain, and relieves the structure of'jar.This interposed substance may be wood, rubber, felt, or any other-durable yielding substance that will ease of the suddenness of thestrain without, by its crushing, allowing the two iron surfaces to comein contact. Wood set into grooves in the angle-irons serves a very goodpurpose.

Having thusfully describcdour invention, what we claim therein as new,and desire to secure by Letters 1. Supporting the angle-irons E upon a.bolt, instead of upon tbechords, substantially as-and for the pure lpose described.

2. We claim, in combination with angle-irons supported upon a. boit,isted of.upon the chords, the inter posing, btween said irons andchords, of; an elastic cushion, subslto'ntialiy as and for t-hc purposedescribed.

' EDWARD DENMEAD,

WENDEL BOLLMAN. Witnesses to EDWARD DENMEAD:

WALTER A. APPLING,

A. S. EDMONSTON. Witness to WENDL BOLLMAN:

f E. D. MILLER,W

A. B. STOUGHTON,

